This invention relates to the transportation of materials, particularly by use of a tractor-trailer combination.
Traditionally, a trailer used in a tractor-trailer combination is designed for one specific purpose, whether it be for carrying a solid, such as gravel or dirt, or a fluid, such as oil. However, once the load hauled by the trailer is delivered to the ultimate destination, the trailer must be returned empty to pick up the next load. The return trip is therefore nonproductive.
U.S. Pat. No. 5,456,520 issued on Oct. 10, 1995 to Adams et al describes a vehicle for transporting alternative substances in alternative containers. The patent discloses an attempt to use a single trailer to carry either a liquid load or a solid load, permitting the trailer to be more productively used in a specific situation where a liquid is to be transported to a site and a solid is to be loaded at the site for return to the original location. This is accomplished in the patent by moving the particular container to be used to the center of the vehicle to provide a balanced load. However, this requires complicated machinery and adjustment of the position of the containers each time the trailer is loaded. A need exists for an improved design to facilitate increased efficiency in use of a trailer.
In accordance with one aspect of the present invention, a trailer is provided for selectively hauling a fluid and a solid. The trailer includes a frame, a first tank for holding the fluid mounted proximate a first end of the frame and a second tank for holding the fluid mounted proximate the second end of the frame. A side dump is mounted on the frame between the first and second tanks for dumping a load therein over at least a first side of the trailer.
In accordance with another aspect of the present invention, a conduit connects the first tank and the second tank. A valve can be positioned in the conduit. With the valve open, the liquid load in the first tank and the second tank can be balanced. With the valve closed, the liquid load in the first tank and the second tank can be different to provide flexibility in load balancing.
In accordance with another aspect of the present invention, a trailer is provided for selectively hauling a fluid and a solid. The trailer includes a frame, a first side dump for holding the solid mounted proximate a first end of the frame and a second side dump for holding the solid mounted proximate the second end of the frame. A tank for holding the fluid is mounted on the frame between the first and second side dumps. The first and second side dumps permit dumping of the contents therein over at least a first side of the trailer.